INVESTIGATING FLUIDIC ENHANCEMENTS FOR SOFT ROBOTIC APPLICATIONS

Abstract

Over the past decade, the field of soft robotics has established itself as uniquely suited for applications that would be difficult or impossible to realize using traditional, rigid robots. However, soft robotic systems suffer from two limitations: (i) the inability for soft robots to withstand and transfer high forces and (ii) the tyranny of interconnects for in which each individual fluidic soft actuator either requires its own power source or for the input fluid to be regulated by external electronic valves. In this dissertation, we investigated how to fluidically enhance soft robotic systems to reduce their inherent limitations through the use of negative pressure via layer jamming for programmable variable stiffness and fluidic control via microfluidic circuitry. More specifically, we investigate the use of layer jamming to enhance soft robotic capabilities in (i) a multifunctional sail, (ii) a soft/rigid hybrid robot, and (iii) a multimode actuator and studied the effects layer decohesion has on the mechanical response of layer jamming composites. We also investigated the efficacy of a PolyJet multi-material additive manufacturing strategy to fabricate complete soft robots with fully integrated microfluidic circuitry components such as microfluidic diodes, capacitors, and transistors under three fluidic analogues of conventional electronic signals: (i) constant-flow (i.e., “direct current (DC)”) input conditions, (ii) “alternating current (AC)”-inspired sinusoidal conditions, and (iii) a preprogrammed aperiodic (“variable current”) input. Having fluidically enhanced soft robotic systems will eliminate the need for electronic valves and processors while enable the capability of withstanding and transferring forces found in normal day to day activities, to accelerate their adaptation into mainstream applications. The work to reduce the inherent disadvantages of soft robotic systems offers unique promise to enable new classes of soft robots.